Abstract: A device for preventing the undesired rotation of a key and cylinder within a sleeve of an automobile steering column ignition assembly. The device prevents rotation of a key from an off position to a lock position, and the consequent locking of the steering wheel, unless an adjacent button is depressed. Rotation is prevented by interference of the button itself with an abutment formed in a flange projecting from a cap covering the outer end of the cylinder. The flange also retains the button in the assembly.

Abstract: A reversible double-bitted key is reconfigured to permit a cylinder lock and key set to fit in the standard architecture of certain American automobiles. Preferably, the maximum required diameter of the cylinder is maintained under 13 millimeters, permitting the cylinder to be placed in standard instrument panel architecture for many American made vehicles. The minimum width of the key is maintained at approximately 4 millimeters, assuring that the key can withstand the torque requirements of the lock systems. This permits a single key to be used in both the primary and secondary locks. The tumbler is configured such that the minimum distance between the outer edge of the key window in the tumbler and the outer perimeter of the tumbler is greater than the thickness of the tumbler, further assuring that the lock can withstand repeated use without fatigue failure.

Abstract: A cylindrical lock and key set with an electronic interlock circuit includes a self-destruct circuit portion which is intercepted, engaged and destructed by an intercept member when the cylinder is forcibly, axially removed from the lock sleeve. A second intercept member may engage the circuit and destruct it when the cylinder is forcibly rotated. Either or both of the intercept members may be located on the cylinder.